EN 15085 CL1 and CL2 welder approvals are SLV-issued, time-limited, and non-portable across notified bodies. The contractor who treats them as a one-time credential discovers the requalification calendar at the wrong moment — typically mid-project, on the second possession window.
What EN 15085 covers
EN 15085 is the European standard governing the welding of railway vehicles and their components. The standard partitions welded work into four execution classes by safety criticality. CL1 is the highest — structural welds on bogie frames, wheel sets, primary load-bearing rail-vehicle assemblies, and rail bridges where a weld failure carries direct safety consequences. CL2 covers structural welds of secondary criticality. CL3 and CL4 cover lower-criticality work — interior fit-out brackets, non-structural fixtures, and welded items where failure does not propagate to vehicle or infrastructure integrity.
EN 15085-2 binds two distinct qualifications. The manufacturer must hold EN 15085-2 manufacturer certification at the relevant class — a workshop-level approval covering welding coordination, WPS/WPQR documentation, and quality-management infrastructure. The welder must, separately, hold EN 15085-2 welder approval scoped to the same class. Both qualifications must be present and scope-matched at the welded joint.
The SLV institutional position
The Schweißtechnische Lehr- und Versuchsanstalt — SLV — is the German notified body issuing EN 15085 welder approvals at scale across European rail-vehicle manufacturing and rail-civil contracting. SLV operates as a federated network of regional institutes: SLV-Berlin, SLV-Halle, SLV-Hannover, SLV-München, SLV-Duisburg, SLV-Mannheim and others, each authorised to issue and renew approvals under the same EN 15085-2 procedure.
SLV approvals are recognised across DACH, Nordic, Benelux and UK rail-vehicle manufacturers and rail-civil contractors via mutual notified-body arrangements. Recognition is not automatic in every direction — a Swiss or French notified body may require re-test under their own witness for specific scopes, particularly where the lot specification imposes domestic-notified-body conditions. The dominant practical reality is that SLV approval functions as the de facto European standard, and a non-SLV approval frequently triggers re-test on entry into a German rail-civil project. The asymmetry runs in one direction: SLV-approved welders travel well into other jurisdictions; non-SLV-approved welders entering Germany frequently do not.
The 2-year approval cycle
EN 15085-2 welder approvals are time-limited. Initial approval is issued after a successful welding test under notified-body witness, with the certificate valid for 2 years for CL1 and CL2 work from the date of test. Continuation across the validity period requires evidence of continuous practice within the approved scope, plus periodic re-confirmation by the employer’s responsible welding coordinator — typically every six months — recorded on the welder’s approval certificate.
Full re-test under witness is required when any of three conditions is met. First, if the approval lapses — the 2-year clock runs out without timely renewal. Second, if the welder breaks scope, executing welds outside the approved process (per ISO 4063), position, material group (per ISO/TR 15608), or equipment class. Third, if the welder has not performed welding within scope for a continuous period exceeding six months, the approval is considered interrupted and re-qualification is required even where the certificate has not formally expired.
The net effect is that a welder’s CL1/CL2 approval carries an effective operational lifecycle of 18-24 months from issue date to the next re-test gate — the formal 2-year validity, modulated by the 6-month interruption rule and the 6-month employer re-confirmation cadence.
The cost of a re-test resolves into four components. The SLV welding-test fee — typically €400-€800 per scope, where scope is the specific combination of process, position and material group — is the headline charge. Witness time consumes a further 1-2 days off-site at the SLV facility, or alternatively notified-body witness travel to a contractor site for a multi-welder batch test. Test-piece materials are paid by the contractor. Welder downtime — 2-5 working days including travel, test preparation, execution, and result issue — sits on the payroll. Aggregated cumulative cost per welder per cycle sits in the €1,500-€3,000 range in fees and downtime, before considering the possession-window impact of pulling a welder out of an active rail-civil programme for re-test.
For a rail-civil prime running 20-40 CL1/CL2 welders against a DB InfraGO Rahmenvereinbarung, the rolling 24-month requalification calendar represents €30,000-€120,000 of cumulative cost — distributed unevenly because welders’ initial approval dates cluster around employer-onboarding events rather than across an even calendar.
The mid-project discovery problem
The contractor who treats EN 15085 approval as a one-time credential discovers the requalification calendar at the wrong moment. Three failure scenarios recur.
Approval lapses mid-possession. A welder enters a possession window with a CL2 approval that expired three weeks earlier — the contractor’s HR system did not flag the renewal. The site safety officer at the start of the possession reads the certificate, identifies the lapse, and removes the welder from the active rail zone. The remaining crew cannot cover the lapsed welder’s scope without breaking their own. The possession window collapses; exposure per the rail possession-window economic framing sits between €40,000 and €90,000 per blown shift.
Welder breaks scope. Mid-project, the contractor needs MAG welding (ISO 4063 process 135) on S355J2W weathering steel for bridge-deck work, but the welder’s current approval covers S235JR carbon steel only — a different ISO/TR 15608 material group. Re-test is required before the welder can execute, and the delivery slip cascades through every dependent civils crew sequenced behind the bridge-deck work.
Cross-border deployment. A welder approved by a Polish or Czech notified body is deployed to a German DB project. The German prime’s QA team requires SLV-recognised approval. The Polish or Czech approval may be recognised under mutual recognition, may not — typically requires SLV review and occasional re-test under SLV witness, particularly where the lot specification names SLV as the witnessing body. The contractor absorbs 2-4 weeks of delay if re-test is required.
The remedy in all three cases is the same: pre-mobilised approval-scope verification per welder per project, with a 6-month rolling calendar of upcoming expiries against the project’s possession-window calendar.
What pre-mobilised approval scope looks like
A rail-civil contractor with a serious 2027-2030 capex book — SuedLink corridor civils, ElbX tunnel works, 2. Stammstrecke München, HS2-equivalent UK rail civils — requires four operational artefacts.
A per-welder approval registry, holding for each welder: the notified body that issued the approval (SLV-Berlin, SLV-Halle, TÜV-Süd, Bureau Veritas, or another); the execution class (CL1, CL2, CL3, CL4); the welding process per ISO 4063 (111 manual metal arc, 121 submerged arc, 135 MAG, 141 TIG); the position (PA, PB, PC, PD, PE, PF, PG, H-L045); the material group per ISO/TR 15608; the initial approval date and current expiry; and the most recent 6-month employer confirmation date.
A rolling 6-month forward calendar of upcoming expiries, scheduled against project mobilisation calendars. A welder cannot be in re-test during the week of a critical shift.
Pre-mobilisation scope matching. Every welder mobilised to a possession or project is verified against the lot’s QA requirements — process, position, material group, class — before the crew is named on the access list, not after.
Multi-notified-body coverage. Where the project crosses jurisdictions, the contractor holds welder approvals across the relevant notified bodies, or where feasible, welders carrying dual approvals. The cost of holding the dual approval is materially lower than discovering at the lot-mobilisation gate that half the crew is non-portable.
Takeaway
EN 15085 CL1 and CL2 welder approvals are time-limited at 2 years, scope-bounded by process, position, material group and execution class, and notified-body-specific in their issuance. The contractor who treats them as a one-time credential discovers the calendar at the wrong moment — typically on the second possession window, when an approval expired during the first window’s idle period. The contractor who pre-mobilises a per-welder approval registry with a 6-month rolling expiry calendar holds the possession windows. The Rail and Bahnbau deployment category is defined by this discipline at the per-welder, per-scope level. The cost differential is the slot, not the welder.
Rail and Bahnbau infrastructure capex through 2030 — SuedLink, ElbX, 2. Stammstrecke München, the UK rail-civil programme — operates against possession-window calendars that do not renegotiate around a lapsed certificate. The requalification calendar is either pre-mobilised or it is discovered.